SUBSTITUTIONAL DIETING 75 



practised, or where it is done, that it is so often unsatis- 

 factory. 



In the case of the horse there are some foodstuffs 

 which are inevitable, and for which no substitute can be 

 found. Such a one is hay in one or other form, and, 

 therefore, it is useless to look about for alternatives. 

 Whatever its price, a horse needs hay, and nothing else 

 can take its place. With corn, however, the case is 

 different. Oats are rightly considered the ideal concen- 

 trated food for horses. To supply all the corn a working 

 horse requires in the form of oats is, however, an 

 expensive method of feeding, and it is usually possible 

 to substitute for part, or even the whole, of the oats fed 

 daily some other foodstuff or mixture of foodstuffs at less 

 cost, and yet without loss of nutritive material to the 

 horse. Alternatively, if the diet is insufficient for the 

 needs of the animal, it is frequently possible by substi- 

 tution to increase the nutritive value without increasing 

 the cost. The choice of foodstuffs suitable for taking 

 the place of oats in the ration is practically limited to 

 maize, barley, rye, wheat, and dried grains, together with 

 beans, peas, or gram, in small amounts. All these sub- 

 stances have high starch-equivalent values, and little 

 waste matter in the form of water, or crude fibre. They 

 vary considerably, however, in protein content, and this 

 variation renders their substitution for oats more com- 

 plicated than it otherwise would be. The first step then, 

 in deciding on a substitute for part of the oats of a 

 ration, is to find the nitrogenous ratio of the complete 

 ration in its original form. If the percentage of protein 

 in the complete ration is high, then it may be that 

 the substitution of 2 or 3 lbs. of oats by means of its 

 equivalent in pure starchy without any protein at all. 



